Origin and diversity of novel avian influenza a H7N9 viruses causing human infection: phylogenetic, structural, and coalescent analyses (H7N9 report)

Highly Pathogenic Avian Influenza A(H5N1) Virus Struck Migratory Birds in China in 2015

Authors: Yuhai Bi, Zhenjie Zhang, Wenjun Liu, Yanbo Yin, Jianmin Hong, Xiangdong Li, Haiming Wang, Gary Wong, Jianjun Chen, Yunfeng Li, Wendong Ru, Ruyi Gao, Di Liu, Yingxia Liu, Boping Zhou, George F. Gao, Weifeng Shi & Fumin Lei

Affiliation: Various Institution

Source: Scientific Reports


Approximately 100 migratory birds, including whooper swans and pochards, were found dead in the Sanmenxia Reservoir Area of China during January 2015. The causative agent behind this outbreak was identified as H5N1 highly pathogenic avian influenza virus (HPAIV). Genetic and phylogenetic analyses revealed that this Sanmenxia H5N1 virus was a novel reassortant, possessing a Clade HA gene and a H9N2-derived PB2 gene. Sanmenxia Clade H5N1 viruses possess the closest genetic identity to A/Alberta/01/2014 (H5N1), which recently caused a fatal respiratory infection in Canada with signs of meningoencephalitis, a highly unusual symptom with influenza infections in humans. Furthermore, this virus was shown to be highly pathogenic to both birds and mammals, and demonstrate tropism for the nervous system. Due to the geographical location of Sanmenxia, these novel H5N1 viruses also have the potential to be imported to other regions through the migration of wild birds, similar to the H5N1 outbreak amongst migratory birds in Qinghai Lake during 2005. Therefore, further investigation and monitoring is required to prevent this novel reassortant virus from becoming a new threat to public health.